Dental hand piece



Aug. 9, 1927.

G. A. TERRY DENTAL HANDPIECE Filed Feb. lO, 1925 Patented Aug. 9, 1927.

UNITED STATES GEORGE A. TERRY, OF BUFFALO,v NEW YORK. I

DENTAL HAND PIECE.

Application filed February This invention relates to a dental hand piece whereby the dentists holds and manipulates the rotary tool which is employed for doing various kindsof vdental work.

Such hand pieces are provided with an outer sheath or enclosing casing whichis removably connected with a frame so as to permit of uncovering the internal mechanism of the hand piece for the purpose of cleaning and lubricating' the working parts and also adjusting and repairing the same when this is necessary. One of the objects of this invention is to provide a fastening whereby the sheath is detachably connected with the frame, which fastening is of simple yand compact consti-notion and will reliably hold the sheath in its proper position on the fianie and which permits of quickly and easily locking the sheath on the frame or unlocking` the saine therefrom.

. Another object of this invention is to improve the means of journaling the shaft on the fra-me and the sheath so as to provide an improved bearing surface and also insure a proper bearing of the sha-ft on the frame and sheath without involving undue expense in manufacture.

kA further object of this invention is to provide simple and efficient means whereby motion is transmitted from the shaft to the bur, bit or tool when the saine is mounted at an angle to the main shaft/by means of an extension of the sheath. f

In the accompanying drawings:

Figure 1 is a longitudinal sect-ion of my improvements embodied in a straight hand piece.

Figure 2 is a cross section taken on the correspondingly numbered line in Fig. 1.

Figure 3 is a fragmentary side elevation, partly broken away7 of the handpiece'shown in Figs. 1 and 2.

Figure 4C is a fragmentary longitudinal section of the front part of an angular hand piece embodying my invention.

Similar characters of reference indicate correspondingY parts in the several views of the drawings.

The frame of the hand piece Vmay be of any suitable and well known construction, that shown in the drawings comprising a transverse head 10, and an angular bracket comprising an inner arm 11 which projects laterally from the head 110, an outer arm 12 which is offset rearwardly from the inner arm and is adapted to be connected witha 1o, 1926. serial No. 87,305.

support, and a web connecting the opposing ends of the a'rins 11 and 12.

Removably mounted in an opening 14 of l also held against turning in this supporting sleeve7 this being preferably accomplished by engaging the inner end of the lpin or key 16 with a flat sided locking face 18 extend ing from the front end of this bearing tube rearwardly and terminating in a forwardly facing shoulder 19 vvwhich locking face'v and stop shoulder 19 areadapted to engage with the inner end of the key or pin 16, as shown in Fig. 1. The bearing 17 is held in this position by means of a set screw 2() passing through a threaded opening 21 in the head' and through an opening l22 in the supporting sleeve and into a notch 23 on the adjacent part of the bearing tube 17. These openings 21 and 22 and the notch 23 are arranged diametrically opposite the pin 16 and locking face 18 which permits the pin 16 to'be passed through the opening 21 for the purpose of engaging` thel same with the supporting sleeve 15 and theframe in assembling the parts. The shaft of the hand piece comprises a rear section 24' and a front section 25 which are detachably connected by means of a screw joint 26. The rear section is provided with a contracted neck 27 which turns in the bearing tube 17 and is detachably mounted therein by means which also operate to hold thesame normally against longitudinal movement when the parts are'asseinb'led for use. In'the preferred construction thisis accomplished by interposing a thrust washer 28 between the front end of the bearing tube 17 and a rearwardly facing' shoulder 29 formed on the rear section of the shaft between its enlarged part of the reduced rear'part 27 of thesame, and a stop screw nut arranged on an eX- ternal screw thread onthe neck 27 and adapted to engage the rear end of the bear! ing tube 17 and a locking screw nut 31 also engaging Vwith this threaded-part of ther shaft and engaging withy the rearl side of the stop nut 30 for the purpose of holdingthe latter against rotation. These screw nuts 30 and 31. are preferably arranged within the rear end of the sleeve 15. Upon removing the set screw 20 the shaft together 'with its bearing` tube may be removed from thesupporting sleeve 15 and then upon renioi ing the screwv nuts 3() and 31 this shaft may be withdrawn forwardly from the bearing` 17 when this becomes necessary for cleaning, repairing, or adjusting the instrument.. Rotary motion is imparted to the shaft by means of la pulley 31 'secured to the rear end of the neck 27 by means of a set screw 33 or other suitable means and adapted te receive a driving belt on its periphery in a manner similar to that new commonly practiced in dental engines. Y

Surrounding the shaft is a tubular sheath 341 which forms a handle which is grasped by the dentist `and whereby the bitof the tool is controlled while doing dental work. This sheath has its` rear part surrounding the front end ofthe supporting sleeve 15 and the same has the front part of its bore constructed in the form of a longitudinal cylindrical bear-ing` 35 in which turns the cylindrical front part 36 of the front section of the shaft. The front end of the sheath 3l is contracted forming an internal rearwardly facing shoulder 37 which is spaced apart from the front end 'of the shaft so that in the assembled position of the parts the front end of the shaft does not engage with the rearwardly facing shoulder 37 but is suphv `rear of the shoulder' 37. By this means considerable latitude is permitted in the manufacture of the shaft and the sheath which permits the same to fit each other properly at their front ends for producing a rotary joint between the same and is therefore less expensive than a joint which made it necessary to accurately lit the front end of the-shaft against a shoulder on the front part of' the shea-th, as has been necessary heretofore.

rllhe tool or bit which is to be rotated by the shaft. for instance a bur 38. is inserted through an opening 39 at the front end of the sheath andthrough an opening t() at the front of the shaft and this bit may be detachably connected with the shaft in any suitable manner the means shown in the drawings, for example, consisting of a contractable chuck 1-1 of tubular form which receives the rear end of the bit lor bur and provided with a plurality of longitudinal slits 41 which render this chuck flexible and permittthe same to contract and grip thev and the engagement of the tapering rear.

ends of the chuck aws with the tapering front end L16 of a clamping sleeve or block /17 which slides lengthwise in the shaft in rear of the chuck. The longitudinal movement of the clamping sleeve 47 for opening and closing the vchuck and causing the saine to either `.release grip the tool inserted therein is effected by means of a clamping rod 48 which has a screw thread engaging` with an internally threaded part 49 on the rear shaft section and bears at` its front end against the rear end of the clamping sleeve f7 while its rear part extends through the rear part of the shaft to the ex terior thereof tand is provided with a but# ton or linger piece 50 whereby the same may be turned.

The quick detachable connection between the sheath and the. frame of the hand piece which embodies my improved fastening mechanism is constructed as follows:V

The rear end of the sheath is contracted so as'to form a reduced neck 51 and a rearwardly facing shoulder 52. This neck moves into an annular recess or pocket '53 on the front side of the Vhead 10 and the shoulder 52 bears against the front side `of this head. provided with an annular groove which is constructed to form an annular forwardly facing abrupt locking shoulder-15%]E and a rearwardlyr tapering` face 55 in front vof said locking shoulder. At its rear end the ucck 51 is tapered or rounded as shown at 70.

Sliding laterally in an opening` 56 ion the head of the frame a end of which is provided with an abrupt rear face. and an inclined front face for engagement respectively with the abrupt face 5ft and the tapering face 55 on the sheath when the latter is moved into its rearmost position and engages `its neck fully with the pocket 53 on the fran'ie, as shown in Fig. 1. This catch is yieldingly held in this position but capable. of being withdrawn readily therefrom by means which are constructed as follows: Y

The numeral 58 is a transversely movable tension rod which is guided on the frame andconnected at its outer end with a rearwardly projecting lugl 59 on the catch and yieldingly drawn inwardly by means of a spring 60 for the purpose ofv holding' the catch 57 in engagement with the locking` groove of the neck 51. The inner part of this tension rod 58 is arranged within a pocket or recess 61 in the arm 11 while the kintern'iediate part of the saine *slidesr in -a bushing G2 which is secured in the outer end of this pocket bymeans of a pin 63.' The spring 60 surrounds the shifting r'od 58 and bears at its inner end against a head G4; at the inner endof this rod, while the outer end of this 'spring bears Vagainst the On its periphery the neck 511s lcatch 57 the inner.

inner end of the bushing 62. The outer part of the shifting rod 58 is reduced so as to.

form an outwardly facing shoulder which is adapted to engage with an inwardlfor the purpose of limiting the outward movement of the shifting or tension rod and thereby prevent the inner' end of thev catch 57 from being wholly withdrawn from the guide opening 56 in the frame.

For the purpose of rassembling the sheath with the frame and retaining the same in position in which it encloses the shaft and other internal parts of the dental hand piece it is only necessary to slip the sheath rearwardly over the supporting sleeve 15 and insert its neck 51 within the pocket 53 until the shoulder 52 of the sheath engages the front side of the frame. In doing this the rounded rear end of the sheath first deflects the catch 57 laterally and when the sheath fronithe frame inl order to permitl its withdrawal therefrom it is only necessary to pull the catch 57 laterally outward by grasping the lug 59 on theouter end thereof which is somewhat enlarged so that it perfor'ms the function of a finger piece for this purpose during which time the spring 60 will be flexed and its resilience will serve to again return this catch to its inner normal position. Y

These means rfor detachably connecting the sheath and frame are very simple and compact -in construction so that they do not interfere with the manipulation of the hand piece while performing dental work. The same contain no delicate parts lwhich are liable to get out of order and they permit of very quickly locking the sheath on the frame as well as unlocking the same therefrom when this becomes necessary, thereby enabling a dentist to open up the hand piece on the market and has been the principal cause for neglecting cleaning and oiling of the instrument .and proper sterilization which should be y.done in order to maintain the same in a sanitary condition and also cause the same to wear longer and Work better when properly cleaned and oiled.

Moreover by means of this quick detachable sheath the dentist may provide a plurality of sheaths for the hand piece which permits of sterilizing one or more sheaths while one is in use on a patient and thus enables the dentist to treat each patient in the most sanitary manner without loss of time, convenience or expense.

lVhen my invention is incorporated in an angular hand piece the same is organized in the manner shown in Fig. 1. In this construction the bur 381, or other dental tool is arranged at an angle to the axis of the main shaft instead of being, in alinement therewith andL mot-ion is transmitted from the main shaft to this bur by means of a rear extension shaft section 8O which may enter but not necessarily be grasped at its rear end by the chuck 11, an intermediate eXtension shaft section 81 which is connected'with the front end of the rear extension shaft section 8O by means of inter-meshing gear wheels 82, 83 said shaft sections 8O and 81 Vbeing` arranged at anfanglel with reference to each other, .and a socket shaft 811 which is arranged at right angles rto the shaft section 8l and receives the bit 381 and is operatively connected with the shaft section 81 by means of intermeshingVv gear Awheels 85 and 86 mounted respectively'on these parts.

The rear extension shaft section 81 is journaled in a bea-ring bushing 87 which is mounted on the frontend of a sheath 341 which is adapted to ,enclose the main shaft sections of the hand piece and to be'connected atits rear end with the. main frame vand in the same manner in which this is done in the construction shown in Figsl, 2` and rlhe intermediate extension shaft section 81 is journaled in a bearing 88 which is connected with'the bushing bearing 8T by means of a tubular bracket 89 havinga screw connection with the front end of the bearing bushing 87 and the intermediate bearing 88. The socket shaft 84: is journaled in a supporting head 98 which is connected by means of a screw joint with the frontend of the extension bearing 88 and is held in this head 98 byy means of a screw cap 90 applied to the lower side thereof andl bearing against the under side of the gear 86, The tooly 381 passes through the socket shaft 84 and is held therein by means` of a latch 91 in a manner well known in dental prac tice. .l

For the purpose of obtaining a positive driving connect-ion between the main shaft and the extension shaft 80 the front end of liz? the fro-nt` shaft section 25 is provided with one or more coupling lugs 92. which are.

adapted to engage with one or more coupliiig lugs 93 on a collar 94 which is secured to the shaft extension 8O and preferably bears against the inner end of the bearing bushing 8.7, as shown in Fig. -l.

lWhen therefore it is desired to use the instrument Vas a straight hand piece the straight shealh shown in Fig. 1 is employed which permits the bur or other tool to be insert-ed directly into the chunk and conev nccted-with the main driving shaft while the bit is in aliiieinent therewith, but when the dental work requires the use of an angularliand piece then the stra-ight sheath shown in Fig. l is removed from the inain shaft Vand the angular sheath and its extension members are used instead by sii'nply slipping the straight portion 3dr-l of the sheath of the angular hand piece lengthwise ovei' the main shaft until the rear end of this sheath is interloched with the fraine at which time the cooperating driving` lugs 92 and 93 of the main driving` .shaft and the auxiliary oi' extension shaft 8O will be brought into their proper positionsl 'for transmitting motion from the inain shaft to the bit.

l claim as my invention:

l.. AA dental hand piece -eoinprising a frame provided with a bearing and a pocket concentric with said bearing, a shaft jonrnaled in said bearing, a tubular sheath sui:- rounding` said shaft and having its rear end arranged in said pocketand provided with an annular groove forming a forwardly facing shoulder, and a catch guided on the frame and movable laterally thereon into and out of engagement with said shoulder;

2. dental hand piece comprising a traine provided wit-h a bearing and a pocket concentric with said bearing, a shaft journaled in said bearing, a tubular sheath surrounding said shaft and liavingits rear end arranged in said pocket and provided .with an annular groove forming a forwardly facing shoulder, a catch guided on the frame and movable laterally thereon into and out of cngagcmeiit with5 said shoulder and resilient ineans for holding said catch yielding-ly in engagement with said shoulder.

3. A dental hand piece comprising a frame .proif'ided with a bearing and a pocket conshoulder, a catch guided on thc frame and.

movable laterally 4thereon into andout of engagement with said shoulder and pro'- vided at its outer end with a lug', a tension rod connected with said lug, and a spring mounted on the frame and operating to draw said rod and catch inwardly.

4l. A dental hand piece comprising frainefprovided with a bear-ing, a pocket concentric with said bearing, a guideway eX- tending laterally from said pocket, and' aY recess arranged on the side of said frame7 a shaft journaled in said bearingj a. tubulaisheath surrounding said shaftand provided atits rear end with a forwardly facing shoulder arranged within said pocket7 a laterally movable catch-arranged in said guideway and adapted to engage its inner end with said shoulder .and provided at its outerend with a lug7 a 'bushing arranged in the outer end of said recess, a tension rod; arranged in said recess and sliding in said bushing and connected at its outer end with said lug and provided at its inner end with a shoulder, anda spring surrounding saidV tension rod and bearing at one end againstl the shoulder on said rod `and at its other endV against said. bushing.

5.1i dental hand. piece comprising a fraii'ie', a supporting sleeve mounted in said frame, a bearing tube arranged' in said sleeve, a shaft `iournaled in said bearing tube' and having a shoulder opposing'I thr` front end of saidr bearing tube, a screw nut 'arranged on said shaft and opposing the rear end of said bearing tube, said beaiingpro vided on its periphery with a. l-:ey seat and a forwardly facing shoulder,vv and a key ar1 ranged on said sleeve. and engaging with sai(l scat and shoulder. e

G. A dental hand piecev comprising a frame, a supporting sleeve mounted in said frame, a bearing tube arranged in said? sleeve, a shaft journaled in said bearing tubey and having a. shoulder opposing theV front;

seatand shoulder, and a set screw arranged on the frame and engaging with said sleeve and tube. y,

7. A dental hand piece comprising a frame, a main shaft journaled on the fraine,r

a'slieath surrounding said inain shaft and detachably connected with said frame, aneX* tension for said sheath, and a drivinl. l mechanism for a bitarianged within said extension and adapted to be positively interloclted with said main shaft and comprising an extension shaft journaled in the front part of said sheath andk co-oiei'ating coupling lugs arranged onA said main sha ft within the sheath and saidl .extension shaft.A l

In testiinony'whereof I hereby niy signature; Y

GEORGE A. 

